1. Field of the Invention
The present invention relates to an air bag case used for an air bag apparatus, and containing an inflator and a bag body which is expanded by the inflator
2. Background Information
There are well-known air bag apparatus mounted in an instrument panel which is positioned in front of a front-seat passenger for protecting a front-seat passenger of a vehicle.
In the air bag apparatus, an air bag case accommodates a long cylindrical inflator and a bag body. In an emergency of the vehicle, the bag body is expanded by generating gas through a peripheral surface of the inflator.
The air bag case is provided in the form of a case by using a main plate and a pair of side plates perpendicular to the longitudinal direction of the inflator. The main plate is curved in a substantially U-shaped form so as to be opposed to a peripheral back portion and peripheral upper and lower portions of the inflator, and to extend toward a bag body expansion opening. The side plate is provided with an inflator containing opening.
In conventional air bags, the main plate and the side plate are separate members, and are connected by welding.
In the conventional air bag case, since the main plate and the side plate are separately provided, it is necessary to connect them by welding. However, a complicated operation is required for welding the entire critical portion having a long distance. Also a high dimensional accuracy can not be obtained. As a result, there are drawbacks of increased manufacturing cost and the like.
Further, when generating gas from the inflator, pressure in the air bag case increases considerably. Therefore, it is necessary to connect the main plate with the side plate with adequate rigidity so as to resist the pressure.